What is the recommended dosing frequency for sumatriptan (Imitrex) for migraine headaches?

Sumatriptan Dosing Frequency for Acute Migraine

Sumatriptan can be repeated at specific intervals depending on the route: oral doses every 2 hours (maximum 200 mg/24 hours), subcutaneous doses every 1 hour (maximum 12 mg/24 hours), and intranasal doses every 2 hours (maximum 40 mg/24 hours), but treatment must be limited to no more than 8-9 days per month to prevent medication-overuse headache. 1, 2, 3

Route-Specific Dosing Intervals

Oral Administration

• Take 25-100 mg at migraine onset; if headache persists or returns after initial improvement, repeat after at least 2 hours 1
• Maximum daily dose is 200 mg in 24 hours 4, 1
• The 50 mg and 100 mg doses provide greater efficacy than 25 mg, though 100 mg may not be significantly better than 50 mg but carries higher adverse event risk 1, 5

Subcutaneous Administration

• Administer 6 mg at onset; may repeat once after 1 hour if needed 2, 1
• Maximum of 12 mg per 24 hours 4, 2
• This route provides the fastest relief (within 15 minutes) and highest efficacy (70-82% response rate) 4, 6

Intranasal Administration

• Give 5-20 mg (one to two sprays in one nostril) at onset; may repeat after 2 hours 2, 7
• Maximum of 40 mg per 24 hours 4, 2

Critical Monthly Frequency Limitation

The most important prescribing consideration is limiting use to no more than twice weekly (approximately 8-9 treatment days per month) to prevent medication-overuse headache, which can transform episodic migraine into chronic daily headache. 3

• This translates to a maximum of approximately 18 tablets per month for oral formulations (9 treatment days × 2 tablets per attack) 3
• The FDA has not established safety for treating more than 4 headaches in a 30-day period 1

Managing Inadequate Response

Trial Period

• Patients must try sumatriptan for 2-3 headache episodes before determining if it is effective 4, 7

If Single Dose Insufficient

• Add an NSAID or acetaminophen rather than increasing triptan frequency 7
• This combination approach is recommended by the American College of Physicians when adequate sumatriptan dosing provides insufficient relief 7

If Consistently Ineffective

• Switch to a different triptan (almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, or zolmitriptan) 7
• Different triptans work for different patients even when one fails 4

Headache Recurrence Management

Approximately 40% of patients experience headache recurrence within 8-12 hours after initial response, which can be effectively treated with a second dose following the minimum interval requirements above. 4, 8

• Recurrence is related to sumatriptan's short half-life (approximately 2 hours) 8
• The second dose must respect the minimum intervals: 2 hours for oral, 1 hour for subcutaneous, 2 hours for intranasal 2, 1

Special Dosing Considerations

After Subcutaneous Injection

• If migraine returns following initial subcutaneous treatment, oral sumatriptan tablets (up to 100 mg/day) may be given with at least 2 hours between the injection and oral dose 1

Hepatic Impairment

• Maximum single dose should not exceed 50 mg orally in patients with mild to moderate hepatic impairment 1

Common Prescribing Pitfall

The 24-hour washout period between sumatriptan and ergotamine-containing medications (including DHE) is mandatory in either direction to avoid severe vasospastic reactions. 2, 7

• Sumatriptan is also contraindicated within 24 hours of another triptan 4, 7
• Concurrent MAOI use is contraindicated 4, 7